Matulewicz Paweł, Orzeł-Gryglewska Jolanta, Kuśmierczak Magda, Jurkowlaniec Edyta
Department of Animal and Human Physiology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
Department of Animal and Human Physiology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
Brain Res Bull. 2014 Aug;107:43-53. doi: 10.1016/j.brainresbull.2014.06.001. Epub 2014 Jun 7.
Glutamate afferents reaching the ventral tegmental area (VTA) affect dopamine (DA) cells in this structure probably mainly via NMDA receptors. VTA appears to be one of the structures involved in regulation of hippocampal theta rhythm, and this work aimed at assessing the role of glutamatergic activation of the VTA in the theta regulation. Male Wistar rats (n=17) were divided into groups, each receiving intra-VTA microinjection (0.5 μl) of either solvent (water), glutamatergic NMDA agonist (0.2 μg) or antagonist (MK-801, 3.0 μg). Changes in local field potential were assessed on the basis of peak power (Pmax) and corresponding peak frequency (Fmax) for the delta (0.5-3 Hz) and theta (3-6 Hz) bands. NMDA microinjection evoked long-lasting hippocampal theta. The rhythm appeared with a latency of ca. 12 min post-injection and lasted for over 30 min; Pmax in this band was significantly increased for 50 min, while simultaneously Pmax in the delta band remained lower than in control conditions. Theta Fmax and delta Fmax were increased in almost entire post-injection period (by 0.3-0.5 Hz and 0.3-0.7 Hz, respectively). MK-801 depressed the sensory-evoked theta: tail pinch could not induce theta for 30 min after the injection; Pmax significantly decreased in the theta band and at the same time it increased in the delta band. Theta Fmax decreased 10 and 20 min post injection (by 0.4-0.5 Hz) and delta Fmax decreased in almost entire post injection period (by 0.3-0.7 Hz). NMDA injection generates theta rhythm probably through stimulation of dopaminergic activity within the VTA.
抵达腹侧被盖区（VTA）的谷氨酸能传入纤维可能主要通过N-甲基-D-天冬氨酸（NMDA）受体影响该结构中的多巴胺（DA）细胞。VTA似乎是参与调节海马θ节律的结构之一，这项研究旨在评估VTA谷氨酸能激活在θ调节中的作用。将雄性Wistar大鼠（n = 17）分成几组，每组接受VTA内微量注射（0.5微升）溶剂（水）、谷氨酸能NMDA激动剂（0.2微克）或拮抗剂（MK-801，3.0微克）。根据δ（0.5 - 3赫兹）和θ（3 - 6赫兹）频段的峰值功率（Pmax）和相应的峰值频率（Fmax）评估局部场电位的变化。NMDA微量注射诱发了持久的海马θ节律。该节律在注射后约12分钟出现潜伏期，并持续超过30分钟；该频段的Pmax在50分钟内显著增加，而同时δ频段的Pmax仍低于对照条件。在几乎整个注射后时期，θ Fmax和δ Fmax均增加（分别增加0.3 - 0.5赫兹和0.3 - 0.7赫兹）。MK-801抑制了感觉诱发的θ节律：注射后30分钟内尾部夹捏不能诱发θ节律；θ频段的Pmax显著降低，同时δ频段的Pmax增加。注射后10分钟和20分钟，θ Fmax降低（降低0.4 - 0.5赫兹），并且在几乎整个注射后时期，δ Fmax降低（降低0.3 - 0.7赫兹）。NMDA注射可能通过刺激VTA内的多巴胺能活动产生θ节律。
